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Engineering by Scientists on Embryo Stirs Criticism

Researchers in New York have created what is believed to be the first genetically engineered human embryo, which critics immediately branded as a step toward “designer babies.”

But the researchers, at Cornell University, say they used an abnormal embryo that could never have turned into a baby.

“This particular piece of work was done on an embryo that was never going to be viable,” said Dr. Zev Rosenwaks, director of the Center for Reproductive Medicine and Infertility at NewYork-Presbyterian/Weill Cornell hospital. He said the purpose of the work was stem cell research.

That did not stop some from criticizing the work, saying that the techniques being developed could be used by others to create babies with genes modified to make them smarter, taller, more athletic or better looking. They also said there should have been more public discussion.

“It’s an important ethical boundary that scientists have been observing,” said Marcy Darnovsky, associate director of the Center for Genetics and Society, a watchdog group in Oakland, Calif. “These scientists, on their own, decided to step over that boundary with no public discussion.”

The Cornell scientists put a gene for a fluorescent protein into the single-celled human embryo. The embryo had three sets of chromosomes instead of two.

After the embryo divided for three days, all the cells in the embryo glowed, Dr. Rosenwaks said. He said the goal of the work was to see if the fluorescent marker would carry into the daughter cells, allowing genetic changes to be traced as cells divided.

The research was presented last fall at a meeting of the American Society for Reproductive Medicine. But it received virtually no attention until last weekend, when The Sunday Times of London published an article after the work was mentioned in a British government review of related technology.

Dr. Rosenwaks said the research was approved by a review board at his medical center and was privately financed, so it did not violate federal restrictions on research involving human embryos.

Doctors already put foreign genes into people as part of gene therapy to treat diseases. But those genetic changes generally cannot be passed on to future generations because they are made to only certain types of cells in the body, like blood cells or muscle cells. Genetic changes made to an embryo would theoretically be heritable if the embryo became a baby.

A spokesman for the National Institutes of Health said the Cornell work would not be classified as gene therapy in need of federal review, because a test-tube embryo is not considered a person under the regulations.

Dr. Mark A. Kay, a gene therapy expert at Stanford University, said the Cornell work did not represent a huge technological advance because the scientists used a modified virus, a common gene therapy technique, to ferry the gene into the embryo.

Dr. Kay said genetic modification of embryos could be useful scientifically, as long as it was not used to make designer babies. “I personally don’t see anything wrong with using these embryos and gene transfer techniques to study important aspects of human development,” he said.

Scientists in Oregon reported in 2001 that they had produced a baby monkey containing a fluorescence gene from a jellyfish. They did it by genetically modifying a female’s egg before it was fertilized, rather than modifying an already fertilized embryo.

A version of this article appears in print on , on page A14 of the New York edition with the headline: Engineering By Scientists On Embryo Stirs Criticism. Order Reprints|Today's Paper|Subscribe